1. Chain initiation in a polycistronic message: sequential versus simultaneous derepression of the enzymes for histidine biosynthesis in Salmonella typhimurium
- Author
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John S. Kovach, Mary Anne Berberich, and Robert F. Goldberger
- Subjects
Salmonella typhimurium ,Formates ,Operon ,Serine ,chemistry.chemical_compound ,Methionine ,RNA, Transfer ,Biosynthesis ,Transferases ,Histidine ,Molecular Biology ,Derepression ,chemistry.chemical_classification ,Multidisciplinary ,Adenine ,Multicistronic message ,Structural gene ,Anti-Bacterial Agents ,Kinetics ,Enzyme ,chemistry ,Biochemistry ,Genetic Code ,Mutation ,Enzyme Repression ,Thymine ,Research Article - Abstract
The pathway for histidinle biosyinthesis in Salmonella typhimurium, elucidated largely through the efforts o:f Dr. B. N. Ames and co-workers, 1-5 is shown in Figure 1. The figure also shows that portioin of the pathway for puriine biosynthesis which involves the further metabolism of 4-amino-5-imidazole carboxamide riboinucleotide (phosphoribosyl-AIC).6 Dr. Phillip Hartmain and his colleagues have shown that the structural genes for the enzymes catalyziing the reactioins of the histidine pathway are localized in a small segment of the bacterial chromosome, the histidine operon.7' 8 The phenomenoni of coordiniate derepressioin of the histidine enzymes was originally described by Ames and Garry, 9 who found that the histidine operon functions as a single unit in response to the level of histidiine available to the organism. Evidence presented by Martin10 inidicates that the histidinie operon is transcribed into a polycistroiiic messenger-RNA, anid studies oIn polarity in the histidine operon7' 11,12 suggest that this messenger-RNA is trainslated from the end which
- Published
- 1967
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